Make setting r_stencilbits more consistent in Team Arena UI

I changed Color Depth options 'Default' to reset r_stencilbits instead
of 0 and '32 bit' to use r_stencilbits 8 instead of not changing the
value. (This matches my q3_ui changes in the previous commit.)

Set r_stencilbits when changing graphics presets like when changing
Color Depth.

code/ui/ui_main.c

@@ -3057,14 +3057,15 @@ static void UI_Update(const char *name) {
 		switch (val) {
 			case 0:
 				trap_Cvar_SetValue( "r_depthbits", 0 );
-				trap_Cvar_SetValue( "r_stencilbits", 0 );
+				trap_Cvar_Reset( "r_stencilbits" );
 			break;
 			case 16:
 				trap_Cvar_SetValue( "r_depthbits", 16 );
 				trap_Cvar_SetValue( "r_stencilbits", 0 );
 			break;
 			case 32:
 				trap_Cvar_SetValue( "r_depthbits", 24 );
+				trap_Cvar_SetValue( "r_stencilbits", 8 );
 			break;
 		}
 	} else if (Q_stricmp(name, "r_lodbias") == 0) {
@@ -3088,6 +3089,7 @@ static void UI_Update(const char *name) {
 				trap_Cvar_SetValue( "r_lodbias", 0 );
 				trap_Cvar_SetValue( "r_colorbits", 32 );
 				trap_Cvar_SetValue( "r_depthbits", 24 );
+				trap_Cvar_SetValue( "r_stencilbits", 8 );
 				trap_Cvar_SetValue( "r_picmip", 0 );
 				trap_Cvar_SetValue( "r_mode", 4 );
 				trap_Cvar_SetValue( "r_texturebits", 32 );
@@ -3103,7 +3105,8 @@ static void UI_Update(const char *name) {
 				trap_Cvar_SetValue( "r_vertexlight", 0 );
 				trap_Cvar_SetValue( "r_lodbias", 0 );
 				trap_Cvar_SetValue( "r_colorbits", 0 );
-				trap_Cvar_SetValue( "r_depthbits", 24 );
+				trap_Cvar_SetValue( "r_depthbits", 0 );
+				trap_Cvar_Reset( "r_stencilbits" );
 				trap_Cvar_SetValue( "r_picmip", 1 );
 				trap_Cvar_SetValue( "r_mode", 3 );
 				trap_Cvar_SetValue( "r_texturebits", 0 );
@@ -3120,6 +3123,7 @@ static void UI_Update(const char *name) {
 				trap_Cvar_SetValue( "r_lodbias", 1 );
 				trap_Cvar_SetValue( "r_colorbits", 0 );
 				trap_Cvar_SetValue( "r_depthbits", 0 );
+				trap_Cvar_Reset( "r_stencilbits" );
 				trap_Cvar_SetValue( "r_picmip", 1 );
 				trap_Cvar_SetValue( "r_mode", 3 );
 				trap_Cvar_SetValue( "r_texturebits", 0 );
@@ -3136,6 +3140,7 @@ static void UI_Update(const char *name) {
 				trap_Cvar_SetValue( "r_lodbias", 2 );
 				trap_Cvar_SetValue( "r_colorbits", 16 );
 				trap_Cvar_SetValue( "r_depthbits", 16 );
+				trap_Cvar_SetValue( "r_stencilbits", 0 );
 				trap_Cvar_SetValue( "r_mode", 3 );
 				trap_Cvar_SetValue( "r_picmip", 2 );
 				trap_Cvar_SetValue( "r_texturebits", 16 );